From cb69788d4d046368c32094e0709c0cb81ace32e3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E8=AE=B8=E6=9D=B0=E5=8F=8B=20Jieyou=20Xu=20=28Joe=29?=
 <jieyouxu@outlook.com>
Date: Mon, 10 Jun 2024 11:37:14 +0000
Subject: [PATCH] run-make: add tip about quick-compile with stage0 rustc

---
 src/tests/compiletest.md | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/src/tests/compiletest.md b/src/tests/compiletest.md
index 0f9cd0552..bdad9b96b 100644
--- a/src/tests/compiletest.md
+++ b/src/tests/compiletest.md
@@ -404,6 +404,18 @@ Two `run-make` tests are ported over to Rust recipes as examples:
 - <https://github.com/rust-lang/rust/tree/master/tests/run-make/CURRENT_RUSTC_VERSION>
 - <https://github.com/rust-lang/rust/tree/master/tests/run-make/a-b-a-linker-guard>
 
+#### Quickly check if `rmake.rs` tests can be compiled
+
+You can quickly check if `rmake.rs` tests can be compiled without having to
+build stage1 rustc by forcing `rmake.rs` to be compiled with the stage0
+compiler:
+
+```bash
+$ COMPILETEST_FORCE_STAGE0=1 x test --stage 0 tests/run-make/<test-name>
+```
+
+Of course, some tests will not successfully *run* in this way.
+
 #### Using Makefiles (legacy)
 
 > NOTE: